1. Field of the Invention
The present invention relates to a magnetic disk device adapted for high-speed access to data.
2. Description of the Prior Art
Improvements in (1) enlarging storage capacity, (2) speeding up access to data, and (3) ensuring reliability have keenly been demanded in the field of magnetic disk devices. The most effective means for enlarging storage capacity is to narrow the gap between a magnetic head and a magnetic disk (usually called the flying height).
With the narrower gap between a magnetic head and a magnetic disk, however, the possibility of contact between both members is increased and so is the risk that data on magnetic disks may be destroyed due to contact damage.
Accordingly, the demands must be satisfied while preventing destruction of data on magnetic disks, to thereby ensure reliability in reading and writing data.
Because a magnetic head and a magnetic disk are made of materials which are not sufficiently resistive to sliding motion therebetween, it has been conventional to create an air film by utilizing a speed of a slider relative to the magnetic disk, mount the magnetic head on the slider flying over the magnetic disk on the air film, and fly the slider at a predetermined flying height in a stable manner. Stated otherwise, a magnetic disk device has been designed so as to avoid direct contact between the magnetic disk and the slider which may destroy data on the magnetic disk.
In order to meet the contradictory demands for preventing contact between the slider and the magnetic disk and reducing the flying height of the slider, as disclosed in Japanese Unexamined Patent Publication No. 63-306514, a conventional magnetic head slider has been arranged such that an air film is created by utilizing a speed of the slider relative to the magnetic disk, a flexible support is provided on the slider flying over the magnetic disk, and a magnetic head is mounted on the lower end of the support. The technique permits the magnetic head to come closer to the magnetic disk without reducing the flying height of the slider.
However, a reduction in the weight of moving parts which is essential to high-speed access of data has not been considered. Also, no consideration has been given to how to make the magnetic head stably follow the magnetic disk, resulting in the possibility that surges (vibrations) of the disk may cause a malfunction in recording and reproducing the data. Further, reduction of external forces acting on the flexible support, such as air flow generated during rotation of the magnetic disk, has not been taken into consideration.
In a conventional magnetic head slider of the type comprising a small-sized and light-weight slider for high-speed access, as disclosed in Japanese Unexamined Patent Publication No. 2-226512, the slider has been formed on a suspension, which serves to bias (press) a magnetic head against the magnetic disk surface, by a film forming process such as sputtering. Thus, because slider composition materials are deposited on the suspension by sputtering or the like to form the slider, there have arisen problems in ensuring the bonding strength between the slider and the suspension, ensuring the slider thickness sufficient for the mounting of the magnetic head, accompanied by difficulties in attaining vertical alignment between the floating surface of the slider and the magnetic head.
In a conventional magnetic head supporting system for a magnetic disk device with an aim of achieving high-speed access and large storage capacity, as disclosed in Japanese Unexamined Patent Publication No. 2-227813, a magnetic head has directly been formed as a thin film on a suspension. However, how to make the magnetic head stably follow a magnetic disk has not been considered in this technique such that the magnetic head cannot satisfactorily follow vibrations of the magnetic disk (such as mechanical vibration due to a motor for rotating the magnetic disk and vibration due to air flow generated by rotation of the magnetic disk). This has raised the problem of causing data read/write errors.
Also, sufficient consideration has not been given to how to ensure reliability while making the distance between the magnetic head and the magnetic disk substantially zero to attain high recording density. Therefore, problems such as abrading the magnetic head and the magnetic disk due to contact therebetween and destroying data on the magnetic disk have been encountered.
Thus, the above conventional magnetic head supporting mechanisms for magnetic disk devices have problems to be solved in (1) narrowing the gap between the magnetic head and the magnetic disk, including contact therebetween, for the purpose of large storage capacity, (2) reducing both size and weight of the slider or dispensing with the slider for the purpose of high-speed access to data, and (3) (i) preventing data from being destroyed due to contact of the slider or magnetic head with the magnetic disk, or ensuring characteristics resistive to sliding so as not to destroy data even upon the occurrence of such contact, and (ii) preventing data read/write errors due to the fact that the magnetic head cannot follow (or stably float or contact) the magnetic disk, for the purpose of satisfactory reliability. It is difficult to solve all these problems at the same time.